How do I play Sudoku?

Fill every row, column and 3×3 box with the digits 1 through 9 exactly once. Start with the given digits, use notes for candidates, and never repeat a digit in a unit. A digit that repeats turns red straight away.

What do Easy, Medium, Hard and Expert mean?

They set how many clues the grid starts with: Easy 40, Medium 33, Hard 28 and Expert 24. Now and then an Expert grid keeps 25, or very rarely 26, when six tries find no sparser grid with one solution. Fewer clues usually means a longer solve, but clue count is not a measured difficulty, so some Hard grids fall quickly. Expert is the sparsest setting here, the one to pick for a very hard puzzle.

Does this Sudoku have one solution?

Yes. The generator removes clues only while a solver still finds exactly one solution, and a check that runs past its step limit keeps the clue. The same solution is used for the completion check, hints and the printed answer key.

Can I print a Sudoku puzzle?

Yes. Print puzzle opens your browser's print dialog with only the starting grid of the current puzzle, large and in black and white, without your entries or notes. Print answers prints the solution on its own sheet. Pick a level and press New puzzle first for a fresh one, and choose Save as PDF in the print dialog to keep it as a file.

Can I use pencil marks, hints and undo?

Yes. Notes on turns the number buttons into pencil marks, kept separately from answers. Undo restores either a digit or a note change. Hint fills the selected square from the solution and marks the session assisted.

Is there a daily Sudoku?

This page makes a new puzzle whenever you press New puzzle. The Daily puzzles page on this site has one Sudoku a day, the same for everyone, easy on Monday and Tuesday and hard on Friday and Saturday.

Does it work on a phone, iPad or Chromebook?

Yes. It runs in a current browser on phones, tablets and computers, with no app, no download and no account. On a touch screen, tap a square and then tap a number under the grid.

Does it have Killer, jigsaw, samurai or 16×16 Sudoku?

This page plays classic 9×9 Sudoku. Killer Sudoku and Sandwich Sudoku have their own pages on this site, and the Sudoku Solver fills in a grid you type. Jigsaw, samurai, X (diagonal), 6×6 and 16×16 grids are not offered.

Is my Sudoku progress saved?

Yes, in this browser only. The current game of each level, with its entries, notes, timer and assisted state, is kept until you start a new puzzle at that level. There is no account or server sync.

Sudoku Online

Play an original 9×9 Sudoku puzzle in your browser, or print it. Choose Easy, Medium, Hard or Expert, enter digits with the keyboard or the number buttons, keep pencil marks with Notes, undo up to 80 steps, and ask for a hint when you are stuck. Every generated board has exactly one solution, proved by a solver before each clue is taken away. Print puzzle gives a clean black and white grid, and Print answers gives its answer key on its own sheet. The timer and one game per level stay only in this browser, and a revealed answer marks the session assisted so the result remains honest.

SUDOKU · EASY · 40 CLUES

Fill every row, column and box

0:00

Difficulty

Choose a square, then press a number.

Keyboard: focus the board, use arrows to choose a square, then press 1–9. Notes are pencil marks kept in this browser. Every generated puzzle has exactly one solution; the level sets the clue count (Easy 40, Medium 33, Hard 28, Expert 24, now and then 25 or, rarely, 26). Print puzzle prints the starting grid without your entries; Print answers prints the solution.

Common questions

How do I play Sudoku?: Fill every row, column and 3×3 box with the digits 1 through 9 exactly once. Start with the given digits, use notes for candidates, and never repeat a digit in a unit. A digit that repeats turns red straight away.
What do Easy, Medium, Hard and Expert mean?: They set how many clues the grid starts with: Easy 40, Medium 33, Hard 28 and Expert 24. Now and then an Expert grid keeps 25, or very rarely 26, when six tries find no sparser grid with one solution. Fewer clues usually means a longer solve, but clue count is not a measured difficulty, so some Hard grids fall quickly. Expert is the sparsest setting here, the one to pick for a very hard puzzle.
Does this Sudoku have one solution?: Yes. The generator removes clues only while a solver still finds exactly one solution, and a check that runs past its step limit keeps the clue. The same solution is used for the completion check, hints and the printed answer key.
Can I print a Sudoku puzzle?: Yes. Print puzzle opens your browser's print dialog with only the starting grid of the current puzzle, large and in black and white, without your entries or notes. Print answers prints the solution on its own sheet. Pick a level and press New puzzle first for a fresh one, and choose Save as PDF in the print dialog to keep it as a file.
Can I use pencil marks, hints and undo?: Yes. Notes on turns the number buttons into pencil marks, kept separately from answers. Undo restores either a digit or a note change. Hint fills the selected square from the solution and marks the session assisted.
Is there a daily Sudoku?: This page makes a new puzzle whenever you press New puzzle. The Daily puzzles page on this site has one Sudoku a day, the same for everyone, easy on Monday and Tuesday and hard on Friday and Saturday.
Does it work on a phone, iPad or Chromebook?: Yes. It runs in a current browser on phones, tablets and computers, with no app, no download and no account. On a touch screen, tap a square and then tap a number under the grid.
Does it have Killer, jigsaw, samurai or 16×16 Sudoku?: This page plays classic 9×9 Sudoku. Killer Sudoku and Sandwich Sudoku have their own pages on this site, and the Sudoku Solver fills in a grid you type. Jigsaw, samurai, X (diagonal), 6×6 and 16×16 grids are not offered.
Is my Sudoku progress saved?: Yes, in this browser only. The current game of each level, with its entries, notes, timer and assisted state, is kept until you start a new puzzle at that level. There is no account or server sync.

Every generated puzzle has exactly one solution, checked by a solver before each clue is removed, and every given agrees with that solution. Conflicts are checked by row, column and 3×3 box; the level sets the clue count, which is not a measured human solving time.